Adding 3rd pontoon

October 24th, 2012, 09:50 PM

Bought a new 25' x 25" with strakes for a good deal and ready to install. I am bolting a 2 x 2 x 1/8 sq tube across the existing riser. They will be 36" long for easy access for bolting to the cross member. Think I will use a U bolt type. My floor allows me space above the crossmember to do so. This allow for the 3rd to be 3" lower in the water than the outside toons.

Comment

Every 3rd one will hit a crossmember, carefully cut off the ones that don't hit off and have them welded back on where you need them to sit, should work out fine.

If you use you same welder just don't let him pressure test it.

Appreciate the opition. What about this? Buy 2pc 25' long 2x2x1/4" and bolt them to the exisisting 3rds risers. Use a template to drill out the cross members on the boat spacing 2' cc. Place that template on the 3rd and pre drill the connection holes in the 3rd making sure none of the 3rd riser foul with cross members on the boat ,

Comment

Your third toon with strakes may be a little overkill. The purpose of the strakes is to get the boat's nosecones out of the water where the boat can run quickly and efficiently. They're also good for carrying large crowds or heavy weights (without strakes.)

But we seldom see a boat with a cabin that has the horsepower to plane off and use the strakes. If you're running 150 horsepower, you should be very careful, as your boat may not be as seaworthy as you'd like it to be. I hope I'm wrong.

And, you'll need to go to a different kind of trailer with the third toon--and have the outside bunks raised high enough for the larger toon to clear the boat frame. The middle toon also needs to be supported.

Good luck on you project.

Comment

Bama, thanks for your comments. I am carring my kids and grand kids on this boat and safety has been my main concern. Most all the weight of this boat is no higher than 3' from the deck. The roof supports weigh 160lbs spread over 19lf. The roof decking weighs the same. The rubber roof weighs 48lbs plus 90lbs for the AC. 24lbs per lf spread down the 19lf. The design / \ to center the top weight inside the pontoons and help with side winds. The pontoons will support 9000lbs at 50% submerged. I have two pontoon out riggers that extend to 14' wide in case of rough water. Lastly I pull a 14' fishing boat and Kayat on top of cabin. The strakes came with the pontoon and the boat is for cruising and staying in the slip.

Comment

And, you'll need to go to a different kind of trailer with the third toon--and have the outside bunks raised high enough for the larger toon to clear the boat frame. The middle toon also needs to be supported.

Your right
Here's an idea I'm thinking about. Modifying this trailer by turning it upside down and extending the present boat supports to fit the 3rd. Cutting the present axel assembly down and position it in a fixed spot inside like it is now. Then, adding a third low profile axel to 8'6", I heard that I could get 1000 to 1500 for my 29' carriage trailer. It's in good shape with good tires. If that is true I would probably sell and get one to fit.